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From "Øyvind Harboe" <oyvind.har...@zylin.com>
Subject Re: On the fly reengineering of database schema
Date Fri, 20 Jul 2007 19:02:56 GMT
On 7/20/07, Andrus Adamchik <andrus@objectstyle.org> wrote:
> > Is there any reason, in principle, why we couldn't read that info
> > during startup of the application? IOW, reengineering on the fly.
>
> No reason - you can totally do it. Cayenne runtime mapping is
> completely dynamic. It's not like we would need to re-enhance Java
> bytecode or anything :-)

IYO, is it easy/difficult? Good/bad idea for what I'm trying to achieve?

Way to go? Should I look at other alternatives?


>
> Andrus
>
>
> On Jul 20, 2007, at 9:42 PM, Øyvind Harboe wrote:
>
> > Currently our Cayenne app has the database field size and types stored
> > in the configuration files that ship with the application. They were
> > generated in the Cayenne modeler.
> >
> > Is there any reason, in principle, why we couldn't read that info
> > during startup of the application? IOW, reengineering on the fly.
> >
> > - It would allow database maintainers to adjust field sizes without us
> > updating Cayenne.
> > We have a lot of variants of the database schema in the field and
> > changing size of a  NVARCHAR or changing an NVARCHAR to a CLOB would
> > be typical operations.
> > - Adding a field to a database table could be done from the
> > database GUI
> > - We would be able to cope easily with the absence or presence of
> > optional table fields
> >
> > The Cayenne modeler would still be useful to choose Java
> > representation of the fields regardless of their type(CLOB, NVARCHAR,
> > CHAR, etc.).
> >
> > We have some database adapters that don't do robust reengineering
> > (FoxBase, MS Access, shudder!), but presumably we could
> > programatically adapt the Cayenne database schema for those/stick with
> > a default one which we do today.
> >
> > --
> > Øyvind Harboe
> > http://www.zylin.com - eCos ARM & FPGA  developer kit
> >
>
>


-- 
Øyvind Harboe
http://www.zylin.com - eCos ARM & FPGA  developer kit

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